Fluid feed method

ABSTRACT

A fluid feeding apparatus and method for feeding a fluid to a point beyond the apparatus, wherein a hollow member is provided having an interior surface which defines a chamber having a first fluid therein. The interior surface tapers toward the chamber axis from an open end of the member to an interior surface boundary axially opposite the open end of the member. A second fluid is injected into the chamber generally toward the opening formed at the open end.

This is a divisional of pending application Ser. No. 689,676 filed Jan.8, 1985 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for feeding fluid to a pointbeyond the apparatus. In another aspect, this invention relates to afluid feeding method.

The present invention is particularly suitable for use in a catalyticcracking environment wherein the fluid is oil feedstock. In such anenvironment, the oil feedstock is fed to a mixing zone where it mixeswith a fluidized catalyst.

In one type of catalytic cracking unit, oil and an atomizing gas, suchas steam are ejected from a plurality of nozzles in an atomizationchamber. The chamber has an open end from which the oil and steam arereleased. Catalyst is introduced across the open end of the chamber soas to mix with the atomized oil. The mixture thus formed then passesinto a riser-reactor where cracking of the oil feedstock takes place ina conventional fashion. Hot catalyst particles flowing into theatomization chamber through its open end can cause erosion of thechamber wall. In addition, any oil which accumulates on the chamber wallmight break down into coke, due to the extreme heat of the chamber wall,and possibly cause some clogging of oil or gas nozzles within thechamber. It is also desirable that a uniform exit velocity of theatomized oil be achieved to attain optimum mixing of catalyst and oil inthe mixing zone.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide animproved atomization chamber.

It is also an object of the present invention to provide an atomizationchamber wherein coke buildup and wall erosion are minimized, and inwhich a relatively uniform exit velocity of atomized oil is achieved.

The above objects are realized in an apparatus and method wherein ahollow member is provided having an interior surface which defines achamber, and wherein the interior surface progressively tapers generallytoward the chamber axis from an open end of the member to a boundaryaxially opposite the open end. The chamber thus formed has a first fluidtherein into which a second fluid is injected generally toward anopening formed at the open end of the member.

According to preferred embodiments of the present invention, a member asdescribed above is utilized to define an atomization chamber in acatalytic cracking unit. In these embodiments, the second fluid is oilfeedstock. Atomization gas is also injected into the chamber foratomizing the oil, wherein the first fluid is a background gas withinthe chamber which includes the atomization gas. In two embodiments,substantially all of the interior surface of the member tapers to theboundary which is at a second end of the member opposite the open end.According to one of these two embodiments, the interior surface isgenerally parabolic in shape, whereas in the other embodiment, theinterior surface is generally conical in shape. According to anotherpair of embodiments, the interior surface of the member comprises firstand second portions, wherein the first portion tapers as described aboveto the boundary, and the second interior portion extends axially towardthe open end such that the second portion has an upper end. The secondportion tapers toward the chamber axis from the boundary to the upperend. Each interior surface portion may be either generally parabolic orconical in shape.

An atomization chamber for a cracker unit constructed according to thepresent invention minimizes the formation of eddies therein caused bybackflow of the background gas within the chamber. These eddies can haveentrained catalyst particles associated therewith, which can causeerosion of the member forming the chamber. The eddies can also causeaccumulation of oil on the member interior surface which can lead tocoke buildup on the interior surface. Thus, since the present inventionminimizes eddies, catalyst erosion and coke buildup are also minimized.In addition, minimizing formation of eddies within the chamber enhancesthe likelihood of a relatively uniform exit velocity of the atomizedoil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of certain features of one type ofcatalytic cracking unit which employs a lift pot.

FIG. 3 is an illustration of a cross-section of the lift pot shown inFIG. 2 as would be seen when viewed along lines 3--3.

FIG. 4 is a cross-sectional view of a generally conical atomizationchamber according to a second embodiment.

FIG. 5 is a cross-sectional view of a generally parabolic atomizationchamber having a protruding interior surface portion according to athird embodiment.

FIG. 6 is a cross-sectional view of a generally conical atomizationchamber having a protruding interior surface portion according to afourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, one type of fluid catalytic cracking unit(FCCU) 2 comprises a reactor 4 and a regenerator 6. The reactor 4comprises a riser reactor or transfer line reactor 7, a catalyst/productseparation zone 8 which usually contains several cyclone separators, anda stripping section or zone 10 in which gas, usually steam such asintroduced from line 12, strips entrained hydrocarbon from the cokedcatalyst, although the invention has applicability to transfer linereactors oriented other than vertically as well. Overhead product fromthe separation zone 8 is conveyed via line 14 to a separation zone 16such as the main fractionator where it is separated, for example, intolight hydrocarbons which are withdrawn from the zone 16 by the line 18,gasoline range liquids which are withdrawn by the line 20, distillateswhich are withdrawn by the line 22, and slurry oils, cycle oils,unreacted feed and the like which can be recycled in the recycle means24 as required.

After being stripped in the zone 10, the cracking catalyst is conveyedfrom the zone 10 to the regenerator 6 by the line 28 for coke burnoff.In the regenerator 6, oxygen containing gas is introduced by a line 30which is connected to a source of oxygen containing gas such as the aircompressor 31 and heater 32. Coke deposits are burned from the catalystin the regenerator 6 forming an effluent gas which is separated from thecatalyst in a separation portion 34 of the regenerator 6 which usuallycontains a plurality of cyclone separators. These flue gases arewithdrawn from the regenerator 6 by the line 36. Hot regeneratedcatalyst passes from the regenerator 6 to a lift pot 37 at the lower endof the riser reactor 7 by line 38, which provides a source of hotcracking catalyst particles for the riser reactor.

The catalyst flow rate through the cracking unit is controlled by valves39 which are positioned in the line 38, preferably in a vertical portionthereof.

In the lift pot 37, catalyst from the line 38 is fluidized with afluidizing gas, usually steam, which is introduced into the lift pot 37by line 41. The oil feedstock is introduced into the lift pot 37 via anozzle cartridge assembly 42 which preferably emits a fine mist axiallyinto the riser or transfer line reactor at the lower end thereof. A line44 is shown as connecting the nozzle cartridge assembly 42 with a sourceof heavy oil feedstock, although the invention can also be used to crackexclusively light oils if desired. A line 45 can then connect the nozzlecartridge assembly with a source of light gas oil, or the like.Atomizing gas such as steam can be added to the nozzle cartridgeassembly 42 by line 46 which connects the nozzle cartridge assembly to asteam source.

The operating conditions for the riser reactor 7 and regenerator 6 canbe conventional. Usually, the temperature in the riser reactor 7 will bein the range of from about 850° to 1050° F. The oil is usually admixedwith steam at a weight ratio of oil to steam in the range of from about6:1 to about 25:1. A catalyst oil weight ratio employed in the riserreactor 7 is generally in the range of from about 2:1 to about 30:1,usually between about 3:1 and about 15:1. Pressure in the riser reactor7 is usually between about 15 and about 60 psia (pounds per square inchabsolute). The cracking catalyst particles generally have a size in therange of from about 20 to about 200 microns, usually between about 40and 80 microns. Flow velocity upward in the vertical section of theriser reactor is generally from about 10 to 30 feet per second in thelower portions and up to between about 40 and about 120 feet per secondin the upper portions. The contact time between the catalyst and oil inthe riser reactor is generally in the range of from about 1 to about 4seconds, usually from 1.5 to about 3 seconds where the oil is injectedinto the bottom of the riser. The regenerator is operated at atemperature typically in the range of from about 1100° to about 1500° F.and is ordinarily provided with sufficient oxygen containing gas toreduce the coke on the catalyst to a level of about 0.5 weight percentor less, preferably less than 0.1 weight percent.

Catalysts suitable for catalytic cracking includes silica alumina orsilica magnesia synthetic microspheres or ground gels and variousnatural clay-type or synthetic gel-type catalysts. Most preferably,fluidizable zeolite-containing cracking catalysts are employed. Suchcatalysts can contain from about 2 to about 20 percent based on totalweight of zeolitic material, such as Y-zeolite, dispersed in a silicaalumina matrix and have an equilibrium B.E.T. surface area in the rangeof 25-250 m² /g and a particle size chiefly in the range of 40 to 80microns.

Referring now to FIG. 2, there is shown a cross-sectional view of liftpot 37. Lift pot 37 includes a generally cylindrical section 37a and agenerally frustoconical section 37b whose upper end is connected to thelower end of riser 7 as shown. Usually, the interior surface 50 will beformed from a refractory material to resist rapid erosion from the hotcatalyst. A nozzle assembly, shown generally at 42, is mounted generallycoaxially within lift pot 37 and serves to house various oil andatomizing steam nozzles which empty into an atomization chamber 52. Oilis accordingly atomized in the chamber so as to exit the chamber andpass up riser 7. As shown, nozzle assembly 42 includes a generallycylindrical wall 54, a frustoconically shaped end wall, and a wall 58which will be described in further detail below in conjunction withdescription of the internal details of the nozzle assembly. Preferably,for maintenance purposes, it is very desirable that the assembly 42 beremovable as a unit. One manner of providing for this is to form a liftpot 37 with a port 59a at its lower end adapted for receiving thegenerally cylindrical exterior surface of the wall 54. A generallyannular flange 59b is positioned around the port. The generallycylindrical exterior surface of the wall 54 is provided with a generallyannular flange 59b mounted thereon sealingly contacting the generallyannular flange 59b at the lower end of the lift pot.

A generally annular space 60, hereinafter called a catalyst liftchamber, is formed between the interior surface 50 of the lift pot andthe exterior surface of nozzle assembly 42. A port 62 is provided in thelift pot such that hot catalyst particles flowing through line 38 maypass into lift chamber 60. Preferably, the cracking catalyst isfluidized prior to being mixed with the oil feed. For catalyst aerationor fluidization, a means 64 is positioned in the catalyst lift chamber60 for distributing a fluidized gas such as steam from steam source 41into the catalyst lift chamber adjacent a lower end of the catalyst liftchamber 60. The means 64 preferably distributes fluidizing gas in thelower portion of lift pot to start vertically upward flow of thecracking catalyst. More preferably, a second means 66 for distributing afluidizing gas such as steam from the source 41 is positioned in thecatalyst lift chamber 60 at a position adjacent or below catalystacceleration zone 68. Usually, the means 64 and 66 will each be formedfrom an annular distributor having a sidewall with a plurality of portstherethrough which connects its interior with circumferentially spacedapart positions in the catalyst lift chamber 60. The ports through thesidewall of the annular distributor constituting the means 64 can beoriented downwardly or upwardly to lift the catalyst introduced into thecatalyst lift chamber 60 via port 62 to the annular distributorconstituting the means 66. The ports through the sidewall of thedistributor 66 will generally be oriented toward the lower end of theriser reactor and toward zone 68. In this manner, the cracking catalystcan be conveyed in dilute phase at a desired velocity throughacceleration zone 68 and generally radially inward past the open upperend 70 into the mouth of the riser 7. Atomized oil exiting chamber 52mixes with the catalyst accordingly so that the mixture flows up riser 7where cracking of the oil continues.

Details of the nozzle assembly 42 will now be set forth. As shown, wall58 has an open upper end 70 which forms an opening, and a lower end 72opposite end 70. An interior surface boundary 73 lies at lower end 72 soas to be adjacent to central nozzle 84 and axially opposite the openingformed at the upper end of wall 58. As used herein and in the appendedclaims, the term "boundary" may include many points along a curve oronly a single point. Wall 58 is connected at its upper end to end wall56, and axially extends toward the bottom end of the nozzle assembly sothat a cavity is formed between the wall 58 and walls 56 and 54. Anannular fluid distributor 74 is provided having a sidewall and aplurality of ports through its sidewall at spaced apart positions alongits length connected to the fluid source 46 and positioned in the cavitybetween the wall 58 and the wall 54 at a position closely adjacent theend wall 56. Steam from distributor 74 serves to cool the nozzleassembly. To further reduce heat penetration from the catalyst liftchamber 60 to the atomization chamber 52, one or more radiationshielding members or baffles 76 can be positioned between the wall 58and the wall 54. The radiation shielding members 76 provide radiationshielding between the walls to reduce heat penetration into theatomization chamber 52 and the possibility of coke buildup. Theradiation shielding members 76 can be in the form of tubular bafflesextending circumferentially around and longitudinally through the cavitybetween walls 54 and 58 and this arrangement is presently preferred. Thetubular baffles 76 are provided with apertures which are preferablyradially nonaligned as between adjacent baffles so as to prevent ormitigate heat penetration by radiation. Other types of radiationshielding, such as bronze turnings, raschig rings and the like can beemployed if desired. The cooling fluid introduced into the cavitybetween the wall 54 and the wall 58 can be withdrawn or exhausted fromthe cracking unit such as via tube or port 78 which also is positionedin flow communication with the cavity.

An interior surface 80 of wall 58 defines chamber 52 which has an axis82. In this particular embodiment, surface 80 is generally parabolic inshape, and oriented such that its base corresponds to upper end 70.Thus, substantially all of the interior surface 80 tapers toward axis 82from the open end to boundary 73 at the lower end 72 of the wall. Asshown, upper end 70 is open, and atomization chamber 52 is in fluidcommunication with lift pot 37. Furthermore, wall 58 is oriented suchthat chamber 52 is generally coaxial with respect to lift pot 37 andriser 7. The length of chamber 52 as measured along axis 82 will dependon steam and oil rates, oil viscosity, oil boiling point and otherparameters.

Various nozzles preferably extend through wall 58 and empty intoatomization chamber 52 so as to inject oil and an atomization fluid,usually steam, into chamber 52. Preferably, a central nozzle 84 extendsthrough wall 58 generally along axis 82 so as to empty into chamber 52near end 72 of wall 58. Nozzle 84 comprises a pipe having turbulencegenerating members 86 which can be pentagonally shaped and mounted tothe inside of the pipe. Members 86 serve to breakup oil flow along thewall thereof where velocities are high enough to result in annulartwo-phase flow. In addition, the central nozzle is preferably connectedto a source of gas oil 45. Steam from distributor 74 can be allowed toleak into chamber 52 through a gap (not shown) between wall 58 andnozzle 84 so as to assist in atomizing gas oils being emptied intochamber 52 from nozzle 84. Due to the parabolic shape of chamber 52, oildroplets which have impinged on surface 80 of the wall travel down tothe central nozzle 84 and are redispersed by the atomization steamflowing from the gap. In this regard, it may be desirable to placeanother annular distributor at a position below that of distributor 74and closely adjacent to wall 58 as an additional source of atomizationsteam. It should be understood that many alternative designs for centralnozzle 84 are possible. For example, nozzle 84 as shown and describedcould be replaced by a nozzle of the type which includes two concentrictubes, wherein the inner tube has a helical vane structure therein. Inthis type of nozzle, the inner tube would be connected to the source ofgas oil, and the annulus formed between the inner and outer tube wouldbe connected to a source of atomization steam.

Nozzle assembly 42 further comprises a plurality of nozzles 88 (only twoof which are shown) circumferentially spaced apart around central nozzle84 and axis 82, and positioned so as to empty into chamber 52 frompositions closely adjacent to interior surface boundary 73. As shown,each nozzle 88 comprises a tubular member connected to a source ofatomizing gas 46, usually steam. Thus, nozzles 88 inject atomizing gasinto chamber 52 to assist in atomizing oil released in the chamber.Additionally, atomizing gas from nozzles 88 assists in redispersing oilwhich has traveled down interior surface 80, and also serves toredisperse dead catalyst which can accumulate at the bottom of thechamber.

A plurality of nozzles 90 and 92 extend through wall 58 so as to emptyinto chamber 52 from positions spaced around axis 82. Most preferably,each nozzle 90 (only one of which is shown in FIG. 2) is a tubularmember connected to a source of topped crude oil 44, and each nozzle 92(only one is shown in FIG. 2) is a shear or whistle type nozzleconnected to a source of slurry oil 47. A portion of the illustratednozzle 92 has been cut away to show internal details. As shown, nozzle92 comprises an outer tube connected to the source of slurry oil, and aninner tube connected to a source of atomizing gas 46. The inner tube iscoaxially positioned within the outer tube, and has a slot in itssidewall which extends only partially around the circumference of theinner tube. Atomizing gas exits the slot in a direction toward axis 82so as to shear slurry oil exiting from the outer tube. As shown, nozzles92 are radially spaced farther from axis 82 than nozzles 90 such thatthe positions from which oil is emptied are spaced likewise. As usedherein, radial distance is measured along lines perpendicular to axis82. By way of example, the longitudinal axis of each nozzle 90 might bepositioned above 0.5R to about 0.8R from axis 82, whereas thelongitudinal axis of each nozzle 92 might be placed about 0.75R to 0.90Rfrom axis 82, where R is the radius of the opening formed at the upperend 70 of wall 58. The slurry nozzles 92 are spaced from axis 82 asdescribed above to maximize the volume in chamber 52 occupied by the jetor spray pattern from the nozzles. Due to the slot in the inner tube ofa nozzle 92, steam exiting from the slot disperses slurry oil in a spraypattern covering only about 118° to about 120° in a direction towardaxis 82. Thus, by maximizing the spacing of nozzles 92 from axis 82, agreater cross-sectional area of the chamber is available for the jet orspray pattern to diverge so as to occupy more volume in the chamber. Aswill be explained in more detail below, maximizing the volume occupiedby jets from the nozzles is desirable, since this tends to minimize theformation of eddies within the chamber. Also, as shown in FIG. 2, slurrynozzles 92 are positioned so as to empty oil into the chamber from aposition closer in axial distance to the chamber opening than theposition from which topped crude oil is emptied from nozzle 90. As usedherein, axial distance is that distance measured along lines parallel toaxis 82. Because of this axial positioning of nozzles 92, atomized oilbeing sprayed in a general horizontal direction does not impingedirectly on nozzles 90. This tends to prevent the development of a thickcoating of oil on nozzles 90 and a consequent coke buildup.

If desired, wear plates or shrouds could be placed around the exposedportions of nozzles 90 and 92 in the chamber to assist in protectingthese nozzles from the erosive effect of catalyst particles flowingthrough the chamber. These wear plates could comprise steel pipes, forexample. Also, gaps can be provided between nozzles 90 and 92 and wall58 through which steam can leak into chamber 52 to further assist inatomization.

Fan or spray type nozzles 94 (only two of which are shown) are alsopreferably provided which extend through wall 58 so as to empty into thechamber at points above nozzles 90 and 92. Nozzles 94 are typicallycircumferentially spaced around axis 82. Each nozzle 94 includes acapped tube having a slit in its sidewall which faces the opening at thetop of the chamber. Steam is supplied to nozzles 84 via a hollow halfring 96 mounted to wall 58 so as to be in fluid communication with thenozzles 94. As shown, half ring 96 is connected to a source of steam 46.Steam from nozzles 94 assists in keeping the interior surface 80 cleanand free of catalyst.

Referring now to FIG. 3, there is shown an illustration of a crosssection of the lift pot of FIG. 2 as viewed along lines 3--3. As shown,nozzles 90 are preferably circumferentially spaced around the chamberaxis and central nozzle 84. Similarly, nozzles 92 are alsocircumferentially spaced around the axis.

Several other embodiments of the present invention will now be describedin reference to FIGS. 4-6. In each figure, only a portion of a nozzleassembly is shown. However, it should be understood that the nozzleassembly could be employed in the lift pot of a cracking unit asillustrated with respect to nozzle assemble 42 in FIGS. 2 and 3. Thestructure of each of a embodiments illustrated in FIGS. 4-6 issubstantially similar to that shown in FIGS. 2 and 3 except for thestructure forming the atomization chamber. In particular, slurry andtopped crude nozzles are positioned similarly. Therefore, FIGS. 4-6 willeach be discussed in regard to the atomization chamber structure only.

Referring now to FIG. 4, a cross-sectional view of a nozzle assembly 442according to the second embodiment is shown. Nozzle assembly 442includes a wall 458 having an interior surface 480 which defines achamber 452. As shown, interior surface 480 is generally conical inshape. The embodiment shown in FIG. 4 resembles the FIG. 2 embodiment,however, in that the interior surface of the wall 458 tapers from openend 470 to boundary 473 at the lower end of the wall.

Referring now to FIG. 5, a third embodiment of the present invention isshown. Here, a nozzle assembly 542 includes a wall 558 and a moldedbuildup of refractory material 597 on the interior surface of the wall.The wall 558 and refractory buildup 597 together make up a member whoseinterior surface defines a chamber 552. The interior surface whichdefines the chamber is made up of a first interior surface portion 598which extends from the upper end of wall 558 to an interior surfaceboundary 573 at the edge of the buildup, and a second interior surfaceportion 597a which comprises the surface of the buildup. The boundary573 is closed, generally circular in this case, and generally coaxialwith respect to the chamber axis. The buildup 597 is formed such thatthe second interior surface portion 597a protrudes from the surroundinginterior surface so as to axially extend from the boundary 573 towardthe chamber opening. In addition, the buildup and its respective secondinterior surface portion 597a has an upper end which lies between thechamber opening and boundary 573. By way of example, end 597b can bepositioned within the chamber to be axially spaced 1/2D to D from theupper end of wall 558, where D is the diameter of the opening formed bythe upper end of the wall. In the embodiment of FIG. 5, each of theinterior surface portions 597a and 598 is generally parabolic in shape,such that first portion 698 tapers toward the chamber axis from end 570to boundary 573, and second portion 597a tapers toward the axis from theboundary to end 597b. In addition, nozzles 588 are positioned to emptyatomizing gas into chamber 552 from a position closely adjacent toboundary 573. A central nozzle 584 extends through the buildup 597 alongthe chamber axis such that it empties into chamber 552 adjacent end597b. In operation, trash such as refractory fragments and catalyst willtend to accumulate in the portion of the chamber between the interiorsurface portions reducing the chance of blocking an oil nozzle.Furthermore, oil and small catalyst particles which accumulate in thismanner will be redispersed by gas from nozzles 588.

Although the second inferior surface portion 597a is described as beingformed by buildup of refractory material, many alternatives to thisstructure are possible. For example, wall 558 could be adapted to definethe second interior surface portion.

Referring now to FIG. 6, there is shown a fourth embodiment of theinvention which has an atomization chamber 652 shaped in a mannersimilar to that in FIG. 5. Here, however, there is provided a generallyconical first interior surface portion 698 and a generally conicalsecond interior surface portion 697a. The first interior surface portion698 forms an acute angle with respect to a plane which orthogonallyintersects the chamber axis. Preferably, this acute angle is greaterthan or equal to the internal angle of friction of the catalyst. Theinternal angle of friction for cracking catalysts is typically about 70°to about 78°. By sloping the first interior surface portion in thismanner, catalyst particles impinging on portion 698 will tend to flow ina downward direction to the region between the interior surfaceportions, where catalyst particles will be redispersed by nozzles 688.Thus, the likelihood of catalyst accumulations and possible clogging ofnozzles 690 and 692 is minimized.

In each of the four embodiments illustrated in FIGS. 2-6, therefore, ahollow member is provided having an interior surface which defines achamber. At least a portion of the interior surface tapers toward thechamber axis from a member open end to an interior surface boundaryaxially opposite the open end. The various nozzles inject oil andatomizing gas in V-shaped jets which generally conform to the shape ofthe chamber as described above. Thus, the shape of the chamber minimizes"dead spaces" in the chamber wherein there is little upward velocityfluid flow. Background gas in the chamber, which is primarily atomizinggas or steam in the illustrated embodiments, tends to backflow into such"dead spaces" which causes eddies to form. These swirling eddies mayhave entrained catalyst associated therewith which can causeconsiderable erosion of the member which defines the chamber. Also,eddies will typically cause oil droplets to accumulate on the interiorsurface of the chamber forming member, such accumulations possiblybreaking down to coke which can clog nozzles. Thus, by reducing thecross-sectional area across the atomization chamber by means of achamber forming member shaped according to the present invention,catalyst erosion and coke buildup in the chamber are minimized due tothe minimizing of eddy formations. This minimization of eddies in theatomization chamber also enhances the likelihood of a relatively uniformexit velocity of atomized oil from the chamber.

Although the preferred embodiments are described as having a backgroundgas substantially comprising steam, it should be understood that otherfluids could conceivably be used. Moreover, a chamber designed accordingto the present invention could be applied to any system in which a needarises to inject one fluid into a chamber having another fluid thereinwhich can backflow as described above to form eddies.

EXAMPLES

The following illustrates how the invention might be used in acommercial unit. Using the equipment described in FIGS. 1, 2 and 3, thefollowing specific conditions can be employed.

    ______________________________________                                        Item                                                                          ______________________________________                                        (34) Regenerator diameter feet-inches (I.D.)                                                                  45' 2"                                        (34) Regenerator length feet-inches                                                                           67' 8"                                        (8)  Reactor (disengager) diameter feet-inch (I.D.)                                                           26' 0"                                        (8)  Reactor (disengager) length feet overall                                                                 54' 0"                                        (7)  Reactor riser diameter I.D. inches                                                                       42"                                           (7)  Reactor riser height feet-inches                                                                         88' 6"                                        (37) Lift pot diameter feet-inches                                                                            7' 0"                                         (37) Lift pot height overall feet-inches                                                                      7' 11"                                        (38) Catalyst conduit diameter (I.D.) feet-inches                                                             2' 2"                                         (39) Catalyst slide valve diameter (I.D.) feet-inches                                                         2' 6"                                         ______________________________________                                                          Re-      Dis-                                               Operating Conditions                                                                            generator                                                                              engager  Reactor                                   ______________________________________                                        Outlet temperature °F.                                                                   1298     928                                                Dilute phase temperature °F.                                                             1312     900                                                Top pressure psia 19.7     24.2                                               Riser inlet temperature °F.  1011                                      Riser feed temperature °F.   702                                       Riser out temperature °F.    951                                       Reactor stripper temperature °F.                                                                  950                                                Stripping steam lb/hr      5500                                               Stripping steam lb/ton catalyst                                                                          7.2                                                Riser cat/oil ratio                 4.3                                       Riser Velocity feet/sec             50                                        Residence time seconds              1.8                                       Catalyst circulation tons/min       12.7                                      Total regenerator air (SCFM)                                                                    85,300                                                      Air blower discharge                                                                            310                                                         temperature °F.                                                        Air blower discharge                                                                            38                                                          pressure psia                                                                 ______________________________________                                        Fresh Feed Oil Charge Volumes                                                 and Temperatures BPD, °API °F.                                                     BPD       °API                                                                          °F.                                ______________________________________                                        Virgin gas oil     10,000    32.8   750                                       Heavy cycle oil    7,200     20.3   780                                       Topped crude       8,000     14.0   800                                       Reslurry oil       2,400     10.9   680                                       Precipitator backwash                                                                            1,200     10.8   480                                       Total fresh feed   28,800    --     --                                        Steam, 125 psig, 500° F.                                               To V. Gas oil perheater lb/hr                                                                    4,000                                                      To slurry nozzle lb/hr                                                                           3,000                                                      All other cartridge stm lb/hr                                                                    11,000                                                     Total steam usage  18,000                                                     ______________________________________                                        Lift Pot                                                                      Item                       Dimension                                          ______________________________________                                        (64,)                                                                              Two 3-inch sch. 160 304 SS. steam                                                                   5 ft 6 in OD                                       (66) rings with 421/2 inch diameter steam                                          holes                                                                    (42) Nozzle cartridge assembly, outside                                                                  4 ft. 4 in                                              refractory diameter                                                           overall height        9 ft 51/4 in                                            Upper end of nozzle cartridge assem-                                                                As described                                            bly rounded with 1/2 inch radius with                                         1/8 inch outer layer of Stellite #1 over                                      a 1/8 inch inner layer of Stellite #6                                         over a nosing bar                                                        (80) Interior surface of wall 58 para-                                             bolically shaped according to the ex-                                         pression x.sup.2 = 7.225y, where the                                          y-axis corresponds to axis 82 and the                                         x-axis is perpendicular to axis 82.                                      (52) Length of chamber     40 in                                                   Diameter of chamber at upper end 70                                                                 34 in                                              (44) 3 Heavy cycle and topped crude                                                                      4 in                                                    feed pipes nom. sch 80 typical                                           (45) 1 Virgin gas oil feed pipe nom sch 80                                                               10 in                                              (46) Dispersion steam pipes and rings 11/2                                                               11/2 in                                                 inch sch. 80 with 2 ft 8 in diameter                                          ring of 11/2-inch sch. 80 with 60 3/16                                        inch steam holes                                                         (47) 3 Reslurry oil and separator back-                                                                  21/2 in O.D.                                            wash feed line 4 in sch. 80 nom. dia-                                                               inside                                                  meter with interior steam pipe of                                                                   4 in O.D.                                               21/2 in diameter sch. 160 typical                                        (50) Lift pot interior refractory surface                                                                6 ft 3 in I.D.                                      (7) Lower end of riser interior                                                                         42 in                                                   refractory I.D.                                                          (68) Catalyst acceleration zone 96 defined                                                               4 to 5 inches                                           between upper surface 92 of end wall                                                                surfaces. Throat                                        56 and interior surface of section 37b                                                              measures about 600                                      of catalyst lift pot 37.                                                                            in.sup.2. Surfaces                                                            converge toward                                                               axis at about a                                                               45° angle.                                  (60) Catalyst lift chamber, annular width                                                                111/2 in                                                with annulus circumferentially 360°                                    around nozzle cartridge assembly                                         (86) Turbulence generating members                                                 welded at 15° angle to axis and                                        pentagonally shaped with overall                                              dimension of 11/4 inch by 2 inch with                                         four rows of deflectors, 16 deflectors                                        per row, rows are staggered                                              (88) Dispersal steam pipes of 1 to 11/2 inch                                       nominal pipe diameter                                                    (90) 3 nozzles, each 4 inch nom. diameter                                                                10.3 in                                                 and circumferentially spaced apart,                                           radius to axis 82 for each nozzle                                        (92) 3 nozzles, each 4 inch nom. diameter                                                                3.6 in                                                  and circumferentially spaced apart                                            11 3/16 inch, radium to axis 82 for                                           each nozzle                                                              (74) Perforated steam ring 1 inch sch. 80                                          3 feet 7 inches in diameter                                              (76) 2 Radiation shielding baffle members,                                         perforated 3/8 inch thick steel plates                                        cylindrical shaped, 1/2 inch diameter                                         holes, 4-inch center line distance be-                                        tween holes, plates are 1 inch apart,                                         holes are misaligned                                                     (94) 10 steam wall sparging nozzles each                                           made of 1-inch SCH 80 pipe capped                                             with 1/2-inch thick circular welded                                           plate, each nozzle extending into                                             parabola 2-inches perpendicular to                                            wall with 120° nozzle slot 1/4 inch wide                               cut parallel with wall, and centerline                                        of nozzle slot 1-inch from cap plate                                          weld                                                                     (59c)                                                                              5 feet-5 inches diameter flange 4                                             inches thick carbon steel with 60-                                            13/8 inch diameter holes on a 60                                              inch bolt circle                                                         ______________________________________                                    

Obviously many modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

That which is claimed is:
 1. A fluid feeding method comprising:injectingan oil feedstock and an atomizing fluid for atomizing the oil feedstockfrom a plurality of nozzles which empty into a chamber defined by theinterior surface of a hollow member which has an axis and an open endwhich defines an opening, wherein at least a portion of the interiorsurface progressively tapers toward the axis from the open end to aninterior surface boundary axially opposite the open end, the oilfeedstock and atomizing fluid being injected from the nozzles into thearea of the chamber within said interior surface portion and toward theopening so as to exit the chamber through the opening, wherein toppedcrude oil is injected from a first position within said chamber andwherein slurry oil is injected from a second position within saidchamber, said second position being radially spaced farther from theaxis than said first position, where radial spacing is measured alonglines perpendicular to the axis; introducing a fluidized crackingcatalyst adjacent to the opening such that the oil feedstock exiting thechamber and the catalyst mix to yield a mixture; and passing the mixturethrough a riser reactor.
 2. A method as recited in claim 1, wherein insaid injecting step, oil feedstock is injected from a central positionin the chamber along the axis and from a plurality of positions in thechamber spaced around the axis.
 3. A method as recited in claim 2,wherein atomizing fluid is injected from a position closely adjacent tothe boundary.
 4. A method as recited in claim 1, wherein the secondposition is closer in axial distance to the opening than the firstposition, axial distance being measured along a line parallel to theaxis.
 5. A method as recited in claim 1, wherein the catalyst flowsgenerally radially inward past the open end to mix with oil feedstockexiting the chamber.